Proteomic identification of resistin as a NET-associated neutrophil activity marker in sepsis

BACKGROUND: Neutrophil extracellular traps (NETs) contribute to organ dysfunction in sepsis, yet clinically accessible biomarkers reflecting NET-associated pathology remain limited. We sought to identify circulating proteins associated with NET formation and evaluate their clinical relevance in sepsis. METHODS: Unbiased proteomic profiling of stimulated human neutrophil supernatants and serum from murine sepsis was performed to identify proteins released during NET formation and elevated in vivo. Candidate biomarkers were selected through integration of these datasets and filtering based on cell type-specific expression profiles, followed by validation in patients with sepsis and healthy controls. RESULTS: Integrative analysis identified five candidate circulating markers associated with NET formation in sepsis: cathelicidin antimicrobial peptide, lactotransferrin, neutrophil gelatinase-associated lipocalin (NGAL), resistin, and histone H4. Among these, resistin, a recently recognized neutrophil-associated protein, and NGAL demonstrated the strongest associations with sepsis-associated complications. Both markers were elevated in patients with sepsis and correlated with circulating cell-free DNA levels. In receiver operating characteristic curve analyses, resistin discriminated multiple organ failure (AUC, 0.83) and disseminated intravascular coagulation (AUC, 0.81), whereas NGAL demonstrated similarly robust performance (AUC, 0.84 and 0.79, respectively). Both markers outperformed conventional clinical parameters for discriminating sepsis-associated complications. CONCLUSIONS: These findings identify resistin as a circulating marker associated with NET formation that captures key features of sepsis-associated immunothrombosis and organ failure and may improve assessment of disease severity and risk stratification.